JP2019522576A - Method and apparatus for cleaning sheets of plastic material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a plastic having a large size floating in a washing tank so that washing and discharging of the plastic piece can be controlled according to the degree of contamination and the plastic piece is prevented from accumulating in the discharge channel and preventing its passage. It is an object to provide a solution that can overcome the difficulties of cleaning and pulling and removing pieces. A method and apparatus for cleaning sheets made of plastic materials derived from industrial waste and agricultural waste and then reusing them as raw materials. The washing tank (10) that houses the water tank (21) is supplied with a sheet of plastic material that has been pre-cut into large, dirty strips (18) and a water stream, and the screw agitator (20) The debris (34) is desorbed from the plastic pieces (18) by the deposition action by generating vigorous stirring of the water tank (21) and recirculating the dirty plastic pieces (18) in the washing tank (10). And separate. The large, clean strip (18 ') of plastic material is free of contaminants (34), and suspended matter in the aquarium (21) is free from the lifting device and the water flow coming out of the washing basin (10). As a result of the combined action, the lifting device comprising the endless belt (27) is lifted and taken out in a floating state along the discharge channel (25). It extends from one side and is supported so that it can tilt freely. [Selection] Figure 3

Description

FIELD OF THE INVENTION The present invention relates to recycling a sheet of plastic material and continuously reusing it as a raw material, and specifically, in the agricultural or industrial fields previously cut into large sized strips. With regard to a method and apparatus for cleaning waste-derived plastic sheets or films, the plastic sheets or films remain stuck to contaminants such as sheets or films of soil, sand, gravel and plastic materials, Or it needs to be cleaned properly to remove another piece of material that was discarded during the course of the work.

  Industrial and agricultural wastes include large quantities of plastic films and sheets, mainly consisting of polyvinyl chloride (PVC) and polyethylene (PE) and other resins, most of which are commercial clean. And the percentage of contaminants that remain attached to the plastic film and sheet after cleaning.

  Conventionally, plastic sheets and films derived from agricultural and industrial waste are crushed and cut into small dimensions of about a few tens of centimeters or less before being washed in an aquarium to remove contaminants. There is a need.

  Currently, cleaning plants and equipment are utilized that are very complex, large in size, and require large amounts of water and valuable energy resources.

  Furthermore, as previously mentioned, pre-cutting plastic films and sheets containing a large amount of contaminants into small dimensions entails rapid wear and / or breakage of conventional cutting mill tools, As a result, maintenance and intervention costs are incurred due to the necessary repair and / or replacement of damaged or worn cutting tools.

BACKGROUND OF THE INVENTION Plants and equipment for cleaning plastic films and sheets derived from agricultural and industrial waste are described, for example, in US Pat. No. 4,196,019, European Patent No. 0094282, US Pat. No. 4,073,661, In European Patent No. 0129518, Chinese Patent No. 20826148, Japanese Patent Application Laid-Open No. 60-127111, US Patent Application Publication No. 2010/032009, and Chinese Utility Model No. 20335540 (U) It is disclosed.

  Specifically, U.S. Pat. No. 4,196,019 shows an apparatus for cleaning plastic obtained from film and / or sheets pre-cut into small-size strips, which is preset. Equipped with a slender storage tank suitable for filling the washing tank to the specified water level, the washing tank being equipped with a blade agitator extending horizontally just below its upper level so as to generate a stirring state The blade stirrer is a horizontal channel located below the lower edge of the baffle that separates a small plastic piece that floats in the wash tank and separates the stir zone from the zone of the latter. From there, the plastic piece is ejected by the rotating drum, but such a solution is quite useful for cleaning large plastic pieces. 'Re not.

  EP 0094282 shows a plant for collecting plastic films and sheets with a plurality of washing tanks connected in series, which again via labyrinth passages. Before being put into a series of wash tanks that are in communication with each other, it must be crushed into small pieces in advance, a single wash tank equipped with a normal blade agitator, The plastic pieces floating in the water are pushed along the discharge channel by a plurality of rotors spaced at appropriate intervals along the discharge channel, and then pulled out of the aquarium by the impeller. Plus, because plastic films and sheets tend to stick to the stirrer blades and to the rotor along the discharge channel Not suitable for cleaning Kkufirumu and sheet as a large strip of the dimensions.

  U.S. Pat. No. 4,073,661 also shows a cleaning device of the kind described above, which is substantially similar to that of U.S. Pat. No. 4,196,019, and the plastic material to be cleaned is again A small piece of plastic that is thrown into a water tank of a washing tank equipped with a horizontal agitator, and the stirring area of the washing tank is separated from the stationary area by a divided baffle extending into the water tank and floats in the washing tank. Is lifted and removed by an endless conveyor, the endless conveyor being partially disposed above the wash basin and along a discharge channel disposed above and extending from one side of the wash basin beyond the water level of the aquarium . Again, this solution is not suitable for direct cleaning of large-sized strips, as is the case with conventional devices.

  EP 0129518 discloses an apparatus for cleaning a sheet of plastic material that has been pre-cut into large strips, for example 150 cm, which comprises a perforated peripheral wall. It consists of a storage tank with a horizontal drum having a tubular shaft with a radial blade and a nozzle for supplying water jets, the drum and the inner shaft being controlled at different rotational speeds.

  A similar solution, in addition to being very bulky and complex, requires a very long cleaning time, represented by about 20-30 minutes, and also removes contaminants that are firmly attached to the plastic material. Difficulties and challenges in discharging the large pieces of plastic that can accumulate between the blades of the rotating shaft may inevitably accompany.

Accordingly, it is possible to sufficiently clean a plastic film or sheet that has been appropriately immersed in a washing water tank and pre-cut into large-sized strips, while greatly reducing the washing time, There is a need to find a structurally and functionally simple alternative solution that can more easily eject plastic pieces at the end of the cleaning phase.

  For this reason, the technical problem to be solved by the present invention is to control the cleaning and discharging of plastic pieces according to the degree of contamination and to prevent the plastic pieces from collecting and preventing their passage in the discharge channel. In addition, the present invention provides a solution capable of overcoming the difficulty of cleaning and pulling out and taking out large plastic pieces floating in the washing tank.

BRIEF DESCRIPTION OF THE INVENTION The above-mentioned problems and typical drawbacks of prior art devices, respectively, clean films and sheets of plastic material, previously cut into large strips according to claim 1. The method is improved by a cleaning device according to claim 8.

  In general, the challenge is to clean plastic films and sheets that have been pre-cut into large strips, vigorously agitate the dirty plastic pieces in the wash tub containing the water tub, the water flow exiting the wash tub, and the discharge channel Clean plastic that floats in the aquarium by pulling clean plastic pieces along the discharge channel by a joint action with a lifting device consisting of an endless belt that extends along and is supported to tilt freely This is solved by a method and apparatus for removing a piece.

  In this way, the large plastic piece is lifted up to the outlet end of the discharge channel by the washing water flow and the lifting belt, and the plastic piece accumulates at the outlet edge of the discharge channel, so that the lifting belt does not move. prevent.

  By adjusting the water level of the tank of the washing tub, for example by the outflow of water flow from the discharge channel, or in the alternative, the outlet edge of the discharge channel is placed directly below the water level of the tank of the washing tub By this, it becomes possible to continuously replenish the water tank of the cleaning tank, and it is possible to minimize water consumption.

  By using the variable speed pulling belt, it is possible to control the residence time of the plastic pieces in the washing tank according to the degree of contamination.

  Preferred embodiments of a plastic film and sheet cleaning apparatus and corresponding method according to the present invention will be disclosed in more detail below with reference to the accompanying drawings.

It is a perspective view of a washing device. FIG. 2 is a longitudinal cross-sectional view along line 2-2 in FIG. FIG. 3 is a longitudinal sectional view similar to FIG. 2, showing the inclined pull-up belt in the raised position. FIG. 4 is a top view of the device partially present in the portion along the broken line 4-4 in FIG. 2. It is a flowchart which shows the washing | cleaning method of an apparatus.

DETAILED DESCRIPTION OF THE INVENTION As shown in FIGS. 1 and 2, suitably pre-cut into large sized strips 18 having dimensions of, for example, a few decimeters and / or meters, for example, dimensions of 50 to 150 cm or more. Further, the film and sheet cleaning apparatus made of a plastic material includes a cylindrical, square or polygonal cleaning tank 10 completed by a conical bottom part 11 or a wall inclined downward, and the bottom part 11 of the cleaning tank. Is further provided with a large sediment discharge pipe 12 which discharges the sediment, which is normally closed by two valves 13, 14 which were soiled during the washing phase. Can be selectively driven by actuators or pneumatic cylinders 15, 16, respectively, for discharging contaminants separated from the plastic piece 18 and settled on the bottom 11. It is.

  As shown in FIG. 4, the cleaning tank 10 includes a screw stirrer 20 disposed eccentrically on the side surface of the cleaning tank 10, and here, a dirty strip 18 made of a plastic material in the cleaning tank 10. A large agitation and recirculation zone is left for agitation and recirculation. The screw stirrer 20 extends downward in the vertical direction and is submerged in a water tank 21 having a preset specified water level 22. The screw stirrer 20 may be of the type with one or more continuous screws having a constant and variable pitch, so that a large amount of stirring is generated and the dirty plastic piece 18 is Appropriately configured to prevent sticking to the screw of the agitator, the screw agitator 20 is operably connected to an electric motor 23 configured to drive the screw agitator 20 at a high rotational speed and is high The number of revolutions causes vigorous agitation of the aquarium 21 and continuous upward recirculation of the dirty plastic piece 18, which tends to pull down heavy contaminants downward in the same aquarium 21 within the washing tub 10. It is suitable for preventing the dirty plastic piece 18 from floating and floating in the water tank 21.

  In the course of the experimental test performed using the cleaning apparatus according to the present invention, the screw stirrer 20 having a screw outer diameter of 500 to 600 mm, instructed to rotate at a speed of 250 to 450 rpm or more, As defined above, good results have been obtained with plastic material 18 pre-cut into large sized strips.

  The washing tub 10 includes a side hopper 24 into which a dirty plastic piece 18 is charged. The hopper 24 draws the dirty plastic piece 18 into the washing tub 10 and continuously refills the water tank of the washing tub. A water distributor 24 'is provided that is configured to provide a suitable wash water flow. The dirty plastic piece 18 is continuously supplied to the discharge hopper 24 by the wash water stream, but instead of the hopper 24, other means for feeding the dirty plastic piece 18 and the wash water stream other than those shown in the figure. Or it is not excluded that the system can be used.

  The cleaning tank 10 includes a discharge channel 25 that discharges the cleaned plastic piece 18 ′ floating in the cleaning tank 21 on the side opposite to the charging hopper 24. The discharge channel 25 has a rear end that is in direct communication with the agitation zone of the water tank 21 via a wide side opening 10 ′ of the cleaning tank 10 and is supplied to the input hopper 24. Along with the outflow of the cleaning water flow generated from the cleaning tank 10, which substantially corresponds to the water flow, it extends in the longitudinal direction to the front discharge end 26C for discharging the strip 18 'made of plastic material.

  Specifically, the discharge channel 25 has an upwardly inclined bottom portion with a first largely inclined bottom wall 26A, and this bottom portion is, for example, the cleaning tank 10 connected to the second bottom wall 26B. And the second bottom wall has a slope that is smaller than the slope of the first bottom wall 26 </ b> A and is greater than the water level 22 of the water tank 21 of the cleaning tank 10. It terminates at the leading edge 26C in the lower position and in the discharge channel 25.

  According to the present invention, the discharge of the cleaned plastic piece 18 ′ along the channel 25 from the cleaning tank 10 by pulling up is a cleaning water flow exiting in a controlled manner from the discharge channel 25, the flow rate of which is the input hopper 24. And a wash water stream substantially corresponding to the flow rate of the water stream pulling up the dirty plastic piece 18 entering the wash tank 10 and a channel 25 in direct communication with the agitation zone of the wash tank 10 as shown in FIG. This is achieved by the combined action of continuous lifting means consisting essentially of an endless belt 27 extending longitudinally from the rear end to the front end 26C of the discharge channel 25.

  The lifting endless belt 27 is wound around the rear drum 28, and its rotating shaft 29 is operatively connected to the electric control motor 30 and the front drum 31 shown in FIG. The rotating shaft 32 of the front drum 31 is located above the water level 22 of the water tank 21, and the belt 27 is slightly inclined upward. As a result, at least one of the lower branches 27A of the lower belt 27A of the pulling belt 27 The rear part is partially submerged in the water stream 21 that continuously exits the washing tub 10 by outflow from the front edge 26C of the channel 25.

  Specifically, the endless belt 27 that pulls up the cleaned plastic piece 18 ′ has a width substantially corresponding to the width of the discharge channel 25 and is disposed at an appropriate interval in the longitudinal direction of the belt 27. In addition, it is configured with a plurality of lateral pads 33.

  Further, the rotating shafts 29 and 32 of the two drums 28 and 31 of the lifting belt 27 are arranged with respect to the bottom wall 26B of the discharge channel 26, and the lifting pad 33 of the lower branch 27A of the belt 27 protrudes into the water flow 21. Thus, the cleaned plastic piece 18 'is pulled up by the endless belt 27 and the water flow that continuously exits the discharge channel and keeps the plastic piece 18' in a buoyant state. , Along the channel 25 from the cleaning bath 10.

  The cleaning apparatus further includes control means (not shown) for controlling the motor of the endless belt 27, which is configured to change the rotational speed of the motor and the speed of the endless belt 27 according to various work requirements. I have.

  The straight speed of the belt 27 can be kept constant or adjusted by increasing or decreasing at an appropriate speed, for example at a speed of 30-40 meters / minute, during the same cleaning operation cycle or at a later operation cycle. Cleaning in this way by adjusting and / or changing the speed of travel of the endless belt 27 and thus adjusting and / or changing the outlet flow rate of the cleaned plastic piece 18 '. The cleaning and residence time of the dirty plastic piece 18 in the tank 10 is controlled and thus varied, depending on the degree of contamination of the plastic piece 18 fed to the hopper 27 and the plastic piece 18 ′ exiting the discharge channel 25. Depending on the desired degree of cleanliness, the cleaning and residence times can be increased or decreased.

  In order to prevent the plastic piece 18 ′ raised along the discharge channel 25 from being pushed under the pad 33, the inclination of the endless belt 27 causes the pad 33 to move along with the lower branch 27 </ b> A of the endless belt 27. Note that it sinks at least partially into the aquarium 21 at a distance from the bottom wall 26B of the 25, slightly smaller than the slope of the bottom wall 26B of the discharge channel, thus the plastic piece 18 '. Is always lifted in the levitated state.

  Depending on the size and characteristics of the soiled plastic piece 18 and the overall structural and functional characteristics of the device, a clean strip 18 ′ of large plastic material may be removed from the bottom wall of the discharge channel 25. The leading edge 26C may become clogged, thereby causing the endless belt 27 to stop moving and stop, as indicated by reference numeral 18 ″ in FIG.

  Another feature of the device and its operating method according to the invention is that the endless belt 27 tilts freely around the axis of rotation 29 of the rear drum 28 as indicated by the reference numeral 27 'in FIG. Thus, the rotation shaft 32 of the front drum 31 is slidable in the guide slot 36 near the front edge of the side wall of the channel 25 at each end. A pad 35 is provided. Thus, when the set 18 ″ of plastic pieces 18 ′ is formed at the front edge 26C at the bottom of the discharge channel 25, the endless belt 27 moved by the control motor 37 is freely lifted, and the set of plastic pieces 18 ′. 18 ″ is pushed out of the front edge of the discharge channel 25 and dropped. Once the set 18 ″ of plastic pieces 18 ′ has been taken out, the belt 27 is lowered again by its own weight and again adopts the operating position of FIG. 2, which is indicated by a broken line in FIG.

  The flow chart of FIG. 5 schematically shows the essential steps of a method for cleaning large plastic pieces during an operating cycle with an apparatus according to the invention.

  In step S <b> 1, the dirty plastic piece 18 is continuously supplied to the hopper 24 and eventually to the water tank 21 accommodated in the cleaning tank 10 together with the cleaning water flow.

  In step S <b> 2, through the strong stirring action of the water tank 21 generated by the stirrer 20, the contaminant 34 attached to the plastic piece 18 is separated, and the contaminant is settled by decantation at the conical bottom 11 of the cleaning tank 10. In step S3, pollutants can be periodically discharged from the conical bottom by opening and closing the valves 13 and 14 in sequence.

  The cleaned strip 18 'made of plastic material floating in the aquarium 21 is pulled up along the discharge channel 25 during step S4, and the endless belt 27 and the discharge, as shown in step S5. Due to the combined action with the water flow coming out of the channel 25, it is kept floating.

  When the obstacle 18 ″ is generated in the discharge channel 25 by the plastic piece 18 ′, the endless belt 27 freely tilts upward (step S6), and pushes the collection 18 ″ of the plastic piece blocking the discharge channel forward, Can be dropped and in this way the normal operating state of the device is automatically restored.

  Apparatus and method for cleaning a sheet of plastic material, previously cut into large strips, suitable for achieving the objects of the invention, as mentioned and illustrated with reference to the examples of the accompanying drawings. Therefore, for the entire apparatus or part of the apparatus, specifically, using a stirrer of a different type from the illustrated stirrer, or claiming For a system that forms a discharge channel and a continuous pulling device that lifts the plastic piece in a floating state without going out of the range, and puts the plastic piece and the washing water flow into a system that agitates the water tank of the washing tank Other modifications or changes can be made.

Claims (14)

A method of cleaning a film and / or sheet made of plastic material and separating contaminants (34), wherein a previously cut large strip of the film or sheet of plastic material is cleaned. A cleaned strip (18) made of plastic material which is put into the water tank (21) of the tank (10), subjected to stirring action, separated from the pollutant (34) and floated on the water tank (21). ′) Is pulled up along the discharge channel (25) by the endless belt (27),
The cleaned plastic piece (18 ') is removed from the discharge channel (25) by the combined action of the endless belt (27) and the water stream exiting the washing tub (10) along the discharge channel (25). And taking out the cleaned plastic piece (18 ') and discharging it in a floating state.   Dirty plastic pieces (18) are continuously supplied to the aquarium (21) by a water flow exiting the washing tub (10) with a flow rate substantially corresponding to the flow rate along the discharge channel (25). A method for cleaning a film and / or sheet made of the plastic material according to claim 1.   2. The plastic material according to claim 1, wherein a possible collection (18 ″) of cleaned strips in the discharge channel (25) is removed by thrust and upward tilting movement of the removal belt (27). A method for cleaning films and / or sheets.   The film of plastic material according to claim 1, characterized in that the screw agitator (20) generates a swirl of the water tank and a recirculation of dirty plastic pieces in the washing tank (10). A method of cleaning the sheet.   The water tank (21) of the cleaning tank (10) is changed by changing the amount of the cleaned plastic piece (18 ') taken out from the cleaning tank (10) along the discharge channel (25). 2. A method for cleaning films and / or sheets of plastic material according to claim 1, characterized in that the residence time of the dirty strips (18) in the interior is varied.   6. From plastic material according to claim 5, characterized in that the residence time of the dirty plastic piece (18) in the washing tub (10) is changed by changing the speed of the endless take-off belt (25). A method of cleaning a film and / or sheet.   7. The plastic material according to claim 5 or 6, characterized in that the residence time of the dirty plastic piece (18) in the washing tank (10) is varied with respect to the degree of contamination and the required cleanliness respectively. A method for cleaning films and / or sheets. 2. An apparatus suitable for cleaning pre-cut large strips (18) of dirty films and / or sheets of plastic material and for separating contaminants (34) by the method according to claim 1. In
A washing tub (10) configured to accommodate the aquarium (21) up to a predetermined water level (22);
An agitator (20) inserted deeply into the water tank (21) of the washing tank (10);
A discharge channel (25) of a cleaned strip (18 ') of plastic material having a bottom wall (26) extending upwardly from said washing tub (10);
An endless conveyor (27) configured to remove a cleaned plastic piece (18 ') from the washing tub (10);
It has a lower branch provided with a pad (33) that extends along the discharge channel (25) and takes out a cleaned plastic piece (18 '), the pad (33) being connected to the discharge channel (25). ) Along the water tank (21) below the water level,
With
The said agitator (20) is comprised by the screw agitator extended in the said water tank (21) perpendicularly | vertically, and the said endless conveyor (27) is supported so that it can incline freely.   The endless conveyor includes a conveyor belt supported by a front drum (31) and a rear drum (28) each having a rotation axis (29, 32), and the endless conveyor (27) is the rear drum (28). 9. The device according to claim 8, characterized in that it is tiltably supported around the axis of rotation (29) of the device.   A rotating shaft (32) provided with sliding blocks (35) in which the front rotating drum (31) of the endless conveyor (27) is movable in the respective side guides (36) in the discharge channel (25). The apparatus of claim 9, comprising:   The discharge channel (25) includes a first inclined bottom wall (26A) extending from the opening (10 ') of the cleaning tank (10) and a first bottom wall (26A) of the discharge channel (25). 9. A device according to claim 8, characterized in that it comprises a second inclined bottom wall (26B) having a lower inclination.   9. The cleaning tank (10) according to claim 8, characterized in that it comprises a hopper (24) for charging dirty plastic pieces (18) and a device (24 ') for supplying and distributing water flow. Equipment.   The cleaning tank (10) includes a conical bottom portion (11) for sinking contaminants (34) and a pair of discharge valves (12, 13) that can be selectively operated in an open / close state. The apparatus according to one or more of claims 8 to 12.   9. A device according to claim 8, characterized in that it comprises means for changing the speed of the endless conveyor (27) so as to remove the cleaned plastic pieces (18 ') along the discharge channel (25). apparatus.

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